The dietary protein and
lipid requirements of post-puerulus western rock lobster, Panulirus
cygnus
B. Glencross, M. Smith, J. Curnow, D. Smith, K.
Williams-2001
Aquaculture, 199(1-2): 119-129
Abstract:
The dietary requirements of post-puerulus western
rock lobster for protein and lipid (fat) were examined in a 6-week, pair-fed
feeding study. Incremented dietary amounts of protein (30%, 35%, 40%, 45%,
50% and 55%) at each of two dietary fat levels (6% and 10%) were examined.
An additional diet of fresh mussels (Mytilus edulis) was included as
a reference.
At the end of the 6-week growth experiment, growth of
the rock lobsters was better when protein levels were greater than 50% of
the diet. Growth of rock lobsters was also significantly greater in diets
with the lower fat levels. The growth of the animals fed the reference diet
was significantly superior to all of the experimental diets. Survival of
animals in all treatments was equal to or greater than 75%. Though there
were some significant differences in survival among treatments, this was not
consistent with any relationship between either protein or fat content of
the diets. The number of moulting events observed in each of the test
treatments was significantly lower than that observed by the mussel-fed
animals. This was consistent with what was observed with the level of growth
difference among the test treatments and the mussel-fed treatment. There
were no significant differences in the number of moulting events among any
of the protein-lipid level treatments.
There were no significant differences among the test
treatments with feed intake on a proportion of body weight basis. This was
in accordance with the pair-feeding protocol of this study. Feed conversion
by the lobsters in each of the test treatments was in accordance with what
was observed in their corresponding growth responses. Diets containing 6%
fat and either 50% or 55% protein had significantly lower FCR values than
all other test diets (2.7:1 and 2.5:1, respectively). The diet that had 10%
fat and 30% protein had the highest FCR (7.6:1) and was significantly higher
than all other diets. There were no other significant differences in feed
conversion among the test treatments.
The results of this study support that post-puerulus Panulirus
cygnus have a very high dietary protein requirement and a poor capacity
to utilise dietary lipid. It should be noted though that the relative growth
of the post-puerulus P. cygnus fed the pelleted diets was
considerably lower than of those fed the reference diet of fresh mussels.
Accordingly, optimal diets derived from this study should be based on fat
levels of about 6% and protein levels equal to or exceeding 55%.
(Fisheries Western Australia, Mariculture Research
and Advisory Unit, Fremantle Maritime Centre, Fleet Street, Fremantle, WA
6160, Australia Tel.: +61-8-9239-8103; fax: +61-8-9239-8105, e-mail: bglencross@fish.wa.gov.au)